Steel reinforcing bar ("rebar") has been used for many years to reinforce poured concrete used in the construction of concrete structures such as bridges, roadways and building columns. While straight rebar rod can be used in that shape in some applications, other applications require that the rebar be fabricated into various shapes depending on the shape of the concrete to be reinforced. Sometimes, the rebar is bent to act as tie rods to hold two or more straight rebar rods together. Other times, the rebar is formed into intricate shapes as the main reinforcement for the concrete.
Many automatic bending machines have been developed over the years to fabricate rebar stock material into the shapes needed. Fairly representative of the prior art is the bending machine shown in U.S. Pat. No. 3,680,347 to Schenck et al.
The Schenck device shows a large reel that carries coiled rebar stock which is to be unwound from the coil and fed into the bending machine. The bending machine includes a cabinet that holds the drive and control means for operating the various elements of the bending machine. Typically, a pair of feed rolls picks up the coiled stock from the large reel and feeds the stock through a series of straightening rolls, through a pair of metering rolls and into the bending head. In response to commands from the electronic controls, the bending head performs a series of eccentric bends to effect the shaping of the stock into the desired configuration, the stock is cut by a shearing device and the rebar piece is finished.
Other rebar fabricating machines have been designed to be used exclusively with straight rod stock. Representative of this prior art is the apparatus shown in U.S. Pat. No. 5,255,708 to Kauffman. The Kauffman device shows a rod stock loader positioned at one end of the cabinet of the bending machine. The rod stock is loaded into a pair of feed rolls and then passes down a channel, into a secondary pair of feed rolls, past a shear head and into a bending head. The bending head, in response to commands from the electronic controls, performs one or more bending operations to create the desired shape of the rebar and the stock is cut to length by a shearing device to create the finished rebar piece.
Bending machine manufacturers have traditionally marketed their products for use either with coiled rod stock or straight rod stock. Unfortunately, the market price of rod stock fluctuates and from time to time coiled stock will be less expensive per foot than straight rod stock and at other times the straight rod stock will be less expensive per foot than coiled stock. Thus, the company that uses a bending machine to fabricate rebar segments either must incur the expense of having two bending machines--one for coil stock and one for straight rod stock--or suffer an economic disadvantage when the price of the stock material for their particular type of bending machine is higher than the price for the other type of stock material.
The present invention is designed to overcome these drawbacks of the prior art machines by providing a machine that can process both available types of stock material--coil stock and straight rod stock. A company using the machine of the present invention can select the most economical steel stock material, depending on the market price or availability, for a particular job. If a particular job requires a particular type of steel, the company can easily use the proper steel without a concern as to whether that steel is available in straight rod stock or coil stock. Full flexibility is provided by one machine so that there is no need to be changing from a straight rod stock machine to a coil stock machine and back depending on the particular job requirements. The company can purchase a single machine that effectively does the work of two conventional rebar fabricating machines.
It is an object of the present invention to provide a single rebar fabricating machine that can process both straight rod stock and coil stock by simply changing the type of stock material that is being fed to the machine.
It is a feature of the present invention that a rebar fabricating machine is provided with a horizontal straightening roll module, a drive module, a vertical straightening roll module, an encoder roll, a shearing device and a bending head combined together in a single machine in a particular orientation so that either straight rod stock or coil stock can be fed through the machine for fabrication of rebar pieces.
It is an advantage of the present invention that a manufacturer of rebar pieces can have a single rebar fabricating machine that can handle either straight rod stock or coil stock so that the rebar pieces can be manufactured using the most economical stock material depending on price and availability as well as need for a particular order.
Other objects, features and advantages of the present invention will become apparent from a consideration of the following detailed description.